shorted sammichSID -please help

[rbv2]

hi all,

 

build my sammichSID 3 years ago with no problems. now i got it back from a friend and the backlight of the display was not working anymore.

i tried to find out whats wrong and found the display backlight is working when powered from a battery.

 

during testing with an led on pins B-/B+ i somehow shorted the little sammichSID. when i turn on the unit all i can see now is the row of black boxes on the screen like without firmware.

it is still doing the start sound and the flashing led sequence in the beginning. I tried to re-upload the firmware but nothing changed.

 

what else can i try? please help.

 

thanks

 

[TK.]

For me it looks like a connection problem between PIC and LCD, because the PIC and the MIDIbox SID application is still running.

 

Best Regards, Thorsten.

[rbv2]

thank you Thorsten.

 

i soldered all the joints again on the lcd connector of the cs-pcb and base-pcb, the pic socket and the trimpots.. but with no success, still black boxes..

 

anything else i can do?

[latigid on]

You might've fried your LCD, that's easy to do. You describe shorting the backlight, well if you've applied a high current across any of the data lines that could knock out some of the circuitry. Do you have the option of using a second backlight for a test? If so, be sure you don't have any shorts that might repeat the process and outcome.

 

[rbv2]

thanks for your reply.

 

unfortunately its the only lcd i have. the lcd is working i guess because it looks like before i uploaded the sid application. black squares in the upper row.

is there another way to test the lcd?

how do i check the connections between lcd and pic?

 

thanks

[sneakthief]

Try the MIOS8 LCD test application:

 

http://www.ucapps.de/mios/lcd_interconnection_test_v2.zip

 

If that doesn't work, try uploading MIOS 1.9g again:

 

http://www.ucapps.de/mios/mios_v1_9g.zip

 

Please read the instructions carefully before uploading and make sure to choose the right version.

[rbv2]

i did the lcd test. all pins show the correct voltage but the lcd doesnt change.. so is it broken like latigid on said?

 

after that i uploaded the mios 1.9g and sammich.hex again, application is up and running but .. still black squares :(

 

is it time to buy new lcd?

 

thanks sneakthief regards from leipzig :)

[Hawkeye]

It is probably fried - but before you replace it, give the contrast pot a try... Solid black boxes sometimes are caused by wrong LCD contrast. But I fear the short sent it to LCD nirvana :-)

 

Many greets,

Peter

[rbv2]

thank you hawkeye!

 

but i still have no clue why the backlight was not working (before shorted).. because all the voltage seems to be correct and the backlight lights up when powered from external battery..

 

found this on ebay:

http://www.ebay.de/itm/DISPLAYTECH-202A-BA-BC-LCD-532-6571-/321314061515?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item4acfcf7ccb

 

does it work as replacement or is there any difference regarding the pins?

Edited February 12, 2014 by rbv2

[ilmenator]

Hope you used a current limiting resistor when connecting the backlight to the battery?!

[rbv2]

yes i did :) thank you

[rbv2]

It is probably fried - but before you replace it, give the contrast pot a try... Solid black boxes sometimes are caused by wrong LCD contrast. But I fear the short sent it to LCD nirvana :-)

 

Many greets,

Peter

unfortunately its not the contrast..